This invention relates to the art of welding and, more particularly, to the encoding of metal welding wire with information pertaining thereto, and to the control of automatic or semi-automatic welding apparatus and processes based on the information extracted from a coded welding wire or from other electronically readable information storage devices encoded with information pertaining to a given welding wire.
The present invention is particularly applicable to the encoding and use of coded filler wire and other electronically readable information storage devices in connection with controlling automatic or semiautomatic arc welding apparatus and processes based on information pertaining to the welding wire. Accordingly, the invention will be described with reference to such welding wire information and the storage and use thereof in conjunction with manual and/or automatic control of a welding process or apparatus. Incorporated herein by reference for background information is U.S. Pat. No. 5,692,700 to Bobeczko which is assigned to the assignee of the present application and which discloses the provision of a bar code on a cover and/or reel to identify the type and size of the welding wire on the reel.
Electric arc welding is a complicated process wherein numerous interrelated and non-interrelated parameters affect the deposition of molten metal to a weld pool in performing a welding operation. One such parameter is the welding wire to be used and, in particular, information pertaining thereto which is useful, for example, in determining processes and apparatus in which its use is best suited and processes and/or apparatus operating parameters for a given wire. Other information, such as the date and time of manufacture, the manufacturing location and the like, can assist in tracing the origin of the wire should a problem occur requiring contact with the manufacturer. Further, information such as the alloy type, wire diameter, control numbers, lubrication levels, and the like is valuable for controlling a given process or apparatus so as to optimize performance and weld quality.
In particular, the quality of automated welding is significantly affected by variations in the welding wire diameter which can vary by +/xe2x88x920.001 inch and still be within welding wire specifications, and such a variation can change the deposition rate by as much as six percent for 0.035 inch diameter wire. Welding wire is drawn, and such diameter variations result from a manufacturer""s efforts to fully extend the life of a die by starting with a die that produces slightly undersized wire within a given specification. The die progressively wears during production, whereby the wire size gradually increases and eventually becomes oversized with respect to the specification. While it is possible to tightly control the wire diameter during production such as by frequent replacement of dies, such production for most practical purposes is economically unacceptable. Another major factor affecting weld quality is a variation in the proportion of major to minor gases in the shielding gas mixture for GMAW or MIG welding. The variation of the proportion of the minor gas from a given standard therefore can significantly alter the heat input and thus the weld size, shape and quality.
In accordance with the present invention, information pertaining to metal welding wire of the foregoing character is magnetically encoded thereon and/or in or on other electrically or electronically readable devices or components such as RFID (radio frequency identification) cards or tags, bar code labels or tabs, ROM, IC (integrated circuit) plates or boards, Touch Memory buttons, and the like. Touch Memory is a registered trademark of Dallas Semiconductor Corporation of Dallas, Tex.
The information pertaining to the welding wire can be in a number of different categories including, for example, generic or fixed information such as the product name and/or trademark, the package type, and the like, and information relevant to the welding wire coiled on a given reel or in a given barrel, such as the alloy chemistry thereof, the weight and/or length of the coiled wire, the date, time and location at which a wire was manufactured, personnel responsible for the manufacturer, and the like. Still another category can be variable information such as the diameter of the wire at locations therealong, the surface condition of the wire, winding or twisting conditions, out-of-roundness of the wire, the location of anomalies such as breaks in the wire, the globular to spray break over voltage, personnel changes during manufacturing, and the like. In addition to encoding information of the foregoing character at the time of manufacturer of the wire, it is also contemplated in accordance with the invention that there can be a write back of information to be recorded at the time of use of the wire, such as the date and time of use so as to enable maintaining a log of usage, and the amount used so as to enable identification of a location in the coil relative to the beginning and terminal ends of the wire.
The encoded information can be extracted prior to use and/or in connection with use of the wire in given welding apparatus. When extracted prior to use, the information enables an operator to manually make the necessary preliminary adjustments of the control system for the welding apparatus for obtaining optimum performance thereof, and/or to select between two or more operating modes. With respect to the encoding of information pertaining to the wire diameter, for example, the diameter can be encoded at predetermined intervals along the length of the wire as it is being manufactured, and the extracting of such information prior to initiating operation of the apparatus enables the operator to adjust parameters of the process or to anticipate times in the process where a parameter such as the speed of the wire feeding device needs to be adjusted, so as to maintain a desired deposition rate in response to diameter variations along the length of the wire. When the encoded information is extracted from the wire or other storage device in connection with the operation of the welding apparatus, the extracted information can be used to automatically configure the control system by adjusting an appropriate parameter or parameters for optimizing the apparatus performance, or to automatically switch between different operating modes of the apparatus such as the spray arc and pulsed arc welding modes mentioned above. Such operating modes are given by way of example only, and many other modes of operation can be selected between depending on the particular welding apparatus and/or process with which the principals of the present invention are used. Likewise, the parameter of wire feed speed is given by way of example only, and it will be appreciated that many other parameters can be controlled and/or adjusted using the principals of the present invention such as, arc voltage, arc current, wave shape, arc length or gap, and gas flow rate to name but a few.
Preferably, encoding on the welding wire or on or in other information storage devices is achieved as the welding wire is drawn during the manufacturing process and, in connection with encoding information on the welding wire, it can be achieved by imprinting magnetic pulses thereon. The encoding on the wire may also be achieved by Manchester encoding or MFM (modified frequency modulation) and at the point of use, the coded information may be read from the wire such as by using Hall Effect, inductive pickup coil technology or a magneto resistive method, after which the code is deciphered and the extracted information visually inspected such as on a video screen, and/or recorded and/or transmitted to the welding apparatus to achieve the foregoing control or switching functions. When reading the wire in conjunction with the operation of welding apparatus, the reading can be accomplished, for example, at the wire feeding device.
As mentioned above, the desired information pertaining to electrode wire can also be encoded in a Touch Memory button, on a RFID card or tag, or on a bar code label or tag which would be scanned at the location of the welding apparatus by appropriate electronic reading devices. A Touch Memory button is a semiconductor memory chip enclosed in a stainless steel canister measuring, for example, about 16 millimeters in diameter and having a height between about three and six millimeters. It can be adhesively or otherwise mounted on an object, such as a welding wire reel or barrel and can read or write in response to a momentary contact. The memory chip is stimulated by a five volt signal through a single wire contact and ground.
An RFID system is similar in application to bar code technology, but uses radio frequency rather than optical signals. The system comprises two major components, namely a reader and a memory tag or card, and these components work together to provide a non-contact type of information retrieval. In this respect, the reader produces a radio frequency magnetic field which is transmitted from the reader by an antenna, and the RFID card or tag contains an antenna which receives the magnetic field signal from the reader and an integrated circuit which converts the incoming signal to an electrical form. The integrated circuit memory contents are transmitted as an electromagnetic signal back to the reader wherein the signal is converted back into an electrical form after which the data is decoded and transmitted to a host computer system. RFID systems can be read only or read/write, and the tag can be either active or passive. An active tag includes a battery to produce a stronger electromagnetic return signal to the reader which increases the extent of the transmission distance between the tag and reader, and RFID systems do not require a direct contact with or a direct line of sight with the reader and are well suited for use in harsh environments. In contrast, bar code and Touch Memory systems,require a relatively clean environment because they rely on optics and direct contact with the encoded component of the system.
Regardless of the information storage system used, scanning for the stored information can take place either prior to or in connection with operation of the welding apparatus to facilitate the foregoing manual or automatic adjustment of the apparatus and thus the welding process so as to manually or automatically provide a welding procedure commensurate with characteristics of the electrode. Again, such encoded information enables the manual or automatic adjustment of the apparatus prior to and/or during operation thereof to, for example, compensate for variations in the characteristics of the electrode. Additionally, the stored information preferably includes data relevant to tracking, product distribution, usage, and the like which can be retrieved at any time for maintaining corresponding records including, at the point or points of usage, an inventory of the quantity of available wire.
It is accordingly an outstanding object of the present invention to provide a method and system for controlling the operation of electric arc welding processes using consumable welding wire based on encoded information pertaining to the wire and extracted at the point of use for selecting between modes of operation and/or controlling operation of a welding process based on the extracted information.
Another object is the provision of a method and system of the foregoing character in which operating parameters of welding apparatus can be adjusted during operation thereof in response to extracted information pertaining to the welding wire and/or the apparatus can be shifted between different operating modes based on the extracted information.
A further object of the invention is to provide a method of encoding metal welding wire with information pertaining to characteristics thereof and/or with information pertaining to operating parameters of a welding process with which the wire can be used.
Yet another object is the provision of welding wire having information magnetically encoded thereon pertaining thereto.
Another object is the provision of an information storage system for welding wire by which a wire manufacturer can track wire production and finished goods inventory and by which a wire consumer can track wire usage and raw material inventory.
Yet a further object is the provision of a system of encoding information relating to welding wire which enables error detection by a consumer to preclude use of the wrong welding wire in connection with a particular welding process.
Still another object is the provision of a method of controlling an electric arc welding process based on information encoded on welding wire used in the process.
A further object is the provision of a system for controlling the operation of electric arc welding apparatus based on information encoded on welding wire used with the apparatus.
Yet another object is the provision of a method of operating an electric arc welding process in one of two operating modes and switching between the modes based on information encoded on welding wire used in the process or encoded in or on electronically readable storage devices separate from the wire per se.
Still a further object is the provision of an improved method of maintaining an inventory of consumables in connection with an arc welding process.